Functionalized elastomers

ABSTRACT

This invention discloses a rubbery polymer which is comprised of repeat units that are derived from (1) at least one conjugated diolefin monomer, and (2) at least one functionalized monomer having of the structural formula:                    
     wherein R represents an alkyl group containing from 1 to about 10 carbon atoms or a hydrogen atom, and wherein R 1  and R 2  can be the same or different and represent hydrogen atoms or a moiety selected from the group consisting of                    
     wherein R3 groups can be the same or different and represent alkyl groups containing from 1 to about 10 carbon atoms, aryl groups, allyl groups, and alkyloxy groups of the structural formula —(CH 2 ) y —O—(CH 2 ) z —CH 3 , wherein Z represents a nitrogen containing heterocyclic compound, wherein R 4  represents a member selected from the group consisting of alkyl groups containing from 1 to about 10 carbon atoms, aryl groups, and allyl groups, and wherein n, x, y and z represents integers from 1 to about 10, with the proziso that R 1  and R 2  can not both be hydrogen atoms.

BACKGROUND OF THE INVENTION

It is important for rubbery polymers that are used in tires, hoses,power transmission belts and other industrial products to have goodcompatibility with fillers, such as carbon black and silica. To attainimproved interaction with fillers such rubbery polymers can befunctionalized with various compounds, such as amines. U.S. Pat. No.4,935,471 discloses a process for preparing a polydiene having a highlevel of affinity for carbon black which comprises reacting a metalterminated polydiene with a capping agent selected from the groupconsisting of (a) halogenated nitrites having the structural formulaX—A—C≡N, wherein X represents a halogen atom and wherein A represents analkylene group containing from 1 to 20 carbon atoms, (b) heterocyclicaromatic nitrogen containing compounds, and (c) alkyl benzoates. Thecapping agents disclosed by U.S. Pat. No. 4,935,471 react with metalterminated polydienes and replace the metal with a terminal cyanidegroup, a heterocyclic aromatic nitrogen containing group or a terminalgroup which is derived from an alkyl benzoate. For example, if the metalterminated polydiene is capped with a nitrile, it will result in thepolydiene chains being terminated with cyanide groups. The use ofheterocyclic aromatic nitrogen containing compounds as capping agentscan result in the polydiene chains being terminated with a pyrrolylgroup, an imidazolyl group, a pyrazolyl group, a pyridyl group, apyrazinyl group, a pyrimidinyl group, a pyridazinyl group, anindolizinyl group, an isoindolyl group, a 3-H-indolyl group, acinnolinyl group, a pteridinyl group, a β-carbolinyl group, aperimidinyl group, a phenanthrolinyl group or the like.

U.S. Pat. No. 4,935,471 also discloses that lithium amides are highlypreferred initiators because they can be used to prepare polydieneswhich are terminated with polar groups at both ends of their polymerchains. The extra polar functionality provided by lithium amides resultsin increased interaction with carbon black resulting in betterpolymer-carbon black dispersion. The lithium amides disclosed by U.S.Pat. No. 4,935,471 include lithium pyrrolidide. U.S. Pat. No. 4,935,471also indicates that preferred initiators include amino alkyl lithiumcompounds of the structural formula:

wherein A represents an alkylene group containing from 1 to 20 carbonatoms, and wherein R₁ and R₂ can be the same or different and representalkyl groups containing from 1 to 20 carbon atoms.

It is also desirable for synthetic rubbers to exhibit low levels ofhysteresis. This is particularly important in the case of rubbers thatare used in tire tread compounds. Such polymers are normally compoundedwith sulfur, carbon black, accelerators, antidegradants and otherdesired rubber chemicals and are then subsequently vulcanized or curedinto the form of a useful article. It has been established that thephysical properties of such cured rubbers depend upon the degree towhich the carbon black is homogeneously dispersed throughout thepolydiene rubber. This is in turn related to the level of affinity thatcarbon black has for the rubber. This can be of practical importance inimproving the physical characteristics of rubber articles that are madeutilizing polydiene rubbers. For example, the rolling resistance andtread wear characteristics of tires can be improved by increasing theaffinity of carbon black to the rubbery polymers utilized therein.Therefore, it would be highly desirable to improve the affinity of agiven polydiene rubber for carbon black and/or silica. This is because abetter dispersion of carbon black throughout polydiene rubbers which areutilized in compounding tire tread compositions results in a lowerhysteresis value and consequently tires made therefrom have lowerrolling resistance. It is also known that a major source of hysteresisis due to polymer chain ends that are not capable of full elasticrecovery. Accordingly, improving the affinity of the rubber chain endsto the filler is extremely important in reducing hysteresis.

U.S. Pat. No. 6,080,835 discloses a functionalized elastomer comprising:a functional group defined by the formula:

where R₁ is a selected from the group consisting of a divalent alkylenegroup, an oxy-alkylene group, an amino alkylene group, and a substitutedalkylene group, each group having from about 6 to about 20 carbon atoms,R₂ is covalently bonded to the elastomer and is selected from the groupconsisting of a linear-alkylene group, a branched-alkylene group, and acyclo-alkylene group, each group having from about 2 to about 20 carbonatoms.

U.S. Pat. No. 5,932,662 discloses a method of preparing a polymercomprising: preparing a solution of one or more anionicallypolymerizable monomers in a solvent; and, polymerizing under effectiveconditions, said monomers in the presence of a polymerization initiatorhaving the formula

wherein R₁ is a divalent alkylene, an oxy- or amino-alkylene having from6 to about 20 carbon atoms; and, R₂ is a linear-alkylene,branched-alkylene, or cyclo-alkylene having from about 2 to about 20carbon atoms, Li is a lithium atom bonded directly to a carbon atom ofR₂; and R₃ is a tertiary amino, an alkyl having from about 1 to about 12carbon atoms; an aryl having from about 6 to about 20 carbon atoms; analkaryl having from about 7 to about 20 carbon atoms; an alkenyl havingfrom about 2 to about 12 carbon atoms; a cycloalkyl having from about 5to about 20 carbon atoms; a cycloalkenyl having from about 5 to about 20carbon atoms; a bicycloalkyl having from about 6 to about 20 carbonatoms; and, a bicycloalkenyl having from about 6 to about 20 carbonatoms; where n is an integer of from 0 to about 10.

U.S. Pat. No. 6,084,025 discloses a functionalized polymer prepared by aprocess comprising the steps of: preparing a solution of a cyclic aminecompound, an organolithium compound, and from 3 to about 300equivalents, based upon one equivalent of lithium, of a monomer selectedfrom vinyl aromatic monomers, and mixtures thereof, where said cyclicamine compound is defined by the formula

where R₂ is selected from the group consisting of an alkylene,substituted alkylene, bicycloalkane, and oxy- or N-alkylamino-alkylenegroup having from about 3 to about 16 methylene groups, N is a nitrogenatom, and H is a hydrogen atom, thereby forming a polymerizationinitiator having the formula A(SOL)_(y)Li, where Li is a lithium atom,SOL is a divalent hydrocarbon group having from 3 to about 300polymerized monomeric units, y is from 0.5 to about 3, and A is a cyclicamine radical derived from said cyclic amine; charging the solutioncontaining A(SOL)_(y)Li with from about 0.01 to about 2 equivalents perequivalent of lithium of a chelating reagent, and an organic alkalimetal compound selected from compounds having the formula R₄OM,R₅C(O)OM, R₆R₇NM, and R₈SO₃M, where R₄, R₅, R₆, R₇, and R₈ are eachselected from alkyls, cycloalkyls, alkenyls, aryls, or phenyls, havingfrom 1 to about 12 carbon atoms; and where M is Na, K, Rb or Cs, andsufficient monomer to form a living polymeric structure; and quenchingthe living polymeric structure.

In the initiator systems of U.S. Pat. No. 6,084,025 a chelating reagentcan be employed to help prevent heterogeneous polymerization. Thereagents that are reported as being useful includetetramethylethylenediamine (TMEDA), oxolanyl cyclic acetals, and cyclicoligomeric oxolanyl alkanes. The oligomeric oxolanyl alkanes may berepresented by the structural formula:

wherein R₉ and R₁₀ independently are hydrogen or an alkyl group and thetotal number of carbon atoms in —CR₉R₁₀-ranges 20 between one and nineinclusive; y is an integer of 1 to 5 inclusive; y′ is an integer of 3 to5 inclusive; and R₁₁, R₁₂, R₁₃, and R₁₄ independently are —H or—C_(n)H_(2n+1), wherein n=1 to 6.

U.S. Pat. No. 6,344,538 discloses functionalized monomers andpolymerized functionalized monomers selected from the group consistingof 2-(N,N-dimethylaminomethyl)-1,3-butadiene,2-(N,N-diethylaminomethyl)-1,3-butadiene,2-(N,N-di-n-propylaminomethyl)-1,3-butadiene,2-(cyanomethyl)-1,3-butadiene, 2-(aminomethyl)-1,3-butadiene,2-(hydroxymethyl)-1,3-butadiene, 2-(carboxymethy)-1,3-butadiene,2-(acetoxymethyl)-1,3-butadiene, 2-(2-alkoxy-2-oxoethyl)-1,3-butadiene,2,3-bis(cyanomethyl)-1,3-butadiene,2,3-bis(dialkylaminomethyl)-l,3-butadiene,2,3-bis(4-ethoxy-4-4-oxobutyl)-1,3-butadiene and2,3-bis(3-cyanopropyl)-1,3-butadiene, and methods for preparing suchfunctionalized diene monomers and polymers.

SUMMARY OF THE INVENTION

The present invention relates to functionalized monomers that can bepolymerized into rubbery polymers having low hysteresis and goodcompatibility with fillers, such as carbon black and silica. Thefunctionalized monomers of this invention are typically incorporatedinto the rubbery polymer by being copolymerized with one or moreconjugated diolefin monomers and optionally other monomers that arecopolymerizable therewith, such as vinyl aromatic monomers. In any case,improved polymer properties are realized because the functionalizedmonomers of this invention improve the compatibility of the rubber withthe types of fillers that are typically used in rubber compounds, suchas carbon black and silica.

This invention more specifically discloses monomers that areparticularly useful for copolymerization with conjugated diolefinmonomers to produce rubbery polymers having better compatibility withfillers. The monomers of this invention have a structural formulaselected from the group consisting of

wherein R represents an alkyl group containing from 1 to about 10 carbonatoms or a hydrogen atom, and wherein R¹ and R² can be the same ordifferent and represent hydrogen atoms or a moiety selected from thegroup consisting of

wherein R3 groups can be the same or different and represent a memberselected from the group consisting of alkyl groups containing from 1 toabout 10 carbon atoms, aryl groups, allyl groups, and alklyoxy groupshaving the structural formula —(CH₂)_(y)—O—(CH₂)_(z)—CH₃, wherein yrepresents an integer from 1 to 10, wherein z represents an integer from1 to 10, wherein Z represents a nitrogen containing heterocycliccompound, wherein R⁴ represents a member selected from the groupconsisting of alkyl groups containing from 1 to about 10 carbon atoms,aryl groups, and allyl groups, and wherein x and represents an integerfrom 1 to about 10, and wherein n represents an integer from about 1 toabout 10, with the proviso that R1 and R2 can not both be hydrogenatoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 1 to about 10, with the proviso that the sumof n and m is at least 4;

wherein n represents an integer from 1 to about 10, and wherein R and R′can be the same or different and represent alkyl groups containing fromabout 1 to about 10 carbon atoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 4 to about 10;

wherein x represents an integer from about 1 to about 10, wherein nrepresents an integer from 1 to about 10 and wherein m represents aninteger from 1 to about 10, with the proviso that the sum of n and m isat least 4;

wherein R represents a hydrogen atom or an alkyl group containing from 1to about 10 carbon atoms, wherein n represents an integer from 1 toabout 10, and wherein m represents an integer from 1 to about 10, withthe proviso that the sum of n and m is at least 4; and

wherein n represents an integer from 0 to about 10, wherein m representsan integer from 1 to about 10, wherein x represents an integer from 1 toabout 10, and wherein y represents an integer from 1 to about 10.

The present invention also reveals a rubbery polymer which is comprisedof repeat units that are derived from (1) at least one conjugateddiolefin monomer, and (2) at least one monomer having a structuralformula selected from the group consisting of

wherein R represents an alkyl group containing from 1 to about 10 carbonatoms or a hydrogen atom, and wherein R¹ and R² can be the same ordifferent and represent hydrogen atoms or a moiety selected from thegroup consisting of

wherein R3 groups can be the same or different and represent a memberselected from the group consisting of alkyl groups containing from 1 toabout 10 carbon atoms, aryl groups, allyl groups, and alklyoxy groupshaving the structural formula —(CH₂)_(y)—O—(CH₂)_(y)—CH₃, wherein yrepresents an integer from 1 to 10, wherein z represents an integer from1 to 10, wherein Z represents a nitrogen containing heterocycliccompound, wherein R⁴ represents a member selected from the groupconsisting of alkyl groups containing from 1 to about 10 carbon atoms,aryl groups, and allyl groups, and wherein x and represents an integerfrom 1 to about 10, and wherein n represents an integer from about 1 toabout 10, with the proviso that R1 and R2 can not both be hydrogenatoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 1 to about 10, with the proviso that the sumof n and m is at least 4;

wherein n represents an integer from 1 to about 10, and wherein R and R′can be the same or different and represent alkyl groups containing fromabout 1 to about 10 carbon atoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 4 to about 10;

wherein x represents an integer from about 1 to about 10, wherein nrepresents an integer from 1 to about 10 and wherein m represents aninteger from 1 to about 10, with the proviso that the sum of n and m isat least 4;

wherein R represents a hydrogen atom or an alkyl group containing from 1to about 10 carbon atoms, wherein n represents an integer from 1 toabout 10, and wherein m represents an integer from 1 to about 10, withthe proviso that the sum of n and m is at least 4; and and

wherein n represents an integer from 0 to about 10, wherein m representsan integer from 1 to about 10, wherein x represents an integer from 1 toabout 10, and wherein y represents an integer from 1 to about 10.

The subject invention further discloses a process for synthesizing arubbery polymer that comprises copolymerizing at least one conjugateddiolefin monomer and at least one functionalized monomer in an organicsolvent at a temperature which is within the range of 20° C. to about100° C., wherein the polymerization is initiated with an anionicinitiator and wherein the functionalized monomer has a structuralformula selected from the group consisting of

wherein R represents an alkyl group containing from 1 to about 10 carbonatoms or a hydrogen atom, and wherein R¹ and R² can be the same ordifferent and represent hydrogen atoms or a moiety selected from thegroup consisting of

wherein R3 groups can be the same or different and represent a memberselected from the group consisting of alkyl groups containing from 1 toabout 10 carbon atoms, aryl groups, allyl groups, and alklyoxy groupshaving the structural formula —(CH₂)_(y)—O—(CH₂)_(z)—CH₃, wherein yrepresents an integer from 1 to 10, wherein z represents an integer from1 to 10, wherein Z represents a nitrogen containing heterocycliccompound, wherein R⁴ represents a member selected from the groupconsisting of alkyl groups containing from 1 to about 10 carbon atoms,aryl groups, and allyl groups, and wherein x and represents an integerfrom 1 to about 10, and wherein n represents an integer from about 1 toabout 10, with the proviso that R1 and R2 can not both be hydrogenatoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 1 to about 10, with the proviso that the sumof n and m is at least 4;

wherein n represents an integer from 1 to about 10, and wherein R and R′can be the same or different and represent alkyl groups containing fromabout 1 to about 10 carbon atoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 4 to about 10;

wherein x represents an integer from about 1 to about 10, wherein nrepresents an integer from 1 to about 10 and wherein m represents aninteger from 1 to about 10, with the proviso that the sum of n and m isat least 4;

wherein R represents a hydrogen atom or an alkyl group containing from 1to about 10 carbon atoms, wherein n represents an integer from 1 toabout 10, and wherein m represents an integer from 1 to about 10, withthe proviso that the sum of n and m is at least 4; and

wherein n represents an integer from 0 to about 10, wherein m representsan integer from 1 to about 10, wherein x represents an integer from 1 toabout 10, and wherein y represents an integer from 1 to about 10.

The present invention also discloses a process synthesizingfunctionalized styrene monomer that comprises reacting a secondary aminein the presence of a strong base to produce the functionalized styrenemonomer.

The subject invention further reveals a tire which is comprised of agenerally toroidal-shaped carcass with an outer circumferential tread,two spaced beads, at least one ply extending from bead to bead andsidewalls extending radially from and connecting said tread to saidbeads, wherein said tread is adapted to be ground-contacting, andwherein said tread is comprised of (I) a filler, and (II) rubberypolymer which is comprised of repeat units that are derived from (1) atleast one conjugated d4olefin monomer, and (2) at least one monomerhaving a structural formula selected from the group consisting of

wherein R represents an alkyl group containing from 1 to about 10 carbonatoms or a hydrogen atom, and wherein R¹ and R² can be the same ordifferent and represent hydrogen atoms or a moiety selected from thegroup consisting of

wherein R³ groups can be the same or different and represent a memberselected from the group consisting of alkyl groups containing from 1 toabout 10 carbon atoms, aryl groups, allyl groups, and alklyoxy groupshaving the structural formula —(CH₂)_(y)—O—(CH₂)_(z)—CH₃, wherein yrepresents an integer from 1 to 10, wherein z represents an integer from1 to 10, wherein Z represents a nitrogen containing heterocycliccompound, wherein R4 represents a member selected from the groupconsisting of alkyl groups containing from 1 to about 10 carbon atoms,aryl groups, and allyl groups, and wherein x and represents an integerfrom 1 to about 10, and wherein n represents an integer from about 1 toabout 10, with the proviso that R¹ and R² can not both be hydrogenatoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 1 to about 10, with the proviso that the sumof n and m is at least 4;

wherein n represents an integer from 1 to about 10, and wherein R and R′can be the same or different and represent alkyl groups containing fromabout 1 to about 10 carbon atoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 4 to about 10;

wherein x represents an integer from about 1 to about 10, wherein nrepresents an integer from 1 to about 10 and wherein m represents aninteger from 1 to about 10, with the proviso that the sum of n and m isat least 4;

wherein R represents a hydrogen atom or an alkyl group containing from 1to about 10 carbon atoms, wherein n represents an integer from 1 toabout 10, and wherein m represents an integer from 1 to about 10, withthe proviso that the sum of n and m is at least 4; and and

wherein n represents an integer from 0 to about 10, wherein m representsan integer from 1 to about 10, wherein x represents an integer from 1 toabout 10, and wherein y represents an integer from 1 to about 10.

DETAILED DESCRIPTION OF THE INVENTION

The functionalized monomers of this invention can be copolymerized intovirtually any type of synthetic rubber. In most cases the functionalizedmonomer will be copolymerized with at least one conjugated diolefinmonomer. Optionally, other monomers that are copolymerizable withconjugated diolefin monomers, such as vinyl aromatic monomers, can alsobe included in the polymerization. In any case, typically from about 0.1phm (parts by weight by 100 parts by weight of monomers) to about 99 phmof the functionalized monomer will be included in the polymerization.More typically, from about 0.2 phm to about 50 phm of the functionalizedmonomer will be included in the rubbery polymer. Good results cannormally be attained by including 0.2 phm to 10 phm of thefunctionalized monomer in the rubbery polymer.

According to this invention, polymerization and recovery of polymer aresuitably carried out according to various methods suitable for dienemonomer polymerization processes. This includes batchwise,semi-continuous, or continuous operations under conditions that excludeair and other atmospheric impurities, particularly oxygen and moisture.The polymerization of the functionalized monomers of the invention mayalso be carried out in a number of different polymerization reactorsystems, including but not limited to bulk polymerization, vapor phasepolymerization, solution polymerization, suspension polymerization,emulsion polymerization, and precipitation polymerization systems. Thecommercially preferred methods of polymerization are solutionpolymerization and emulsion polymerization.

The polymerization reaction may use a free radical initiator, a redoxinitiator, an anionic initiator, or a cationic initiator. The preferredinitiation system depends upon the particular monomers being polymerizedand the desired characteristics of the rubbery polymer beingsynthesized. In emulsion polymerizations free radical initiators aretypically utilized. In solution polymerizations anionic initiators, suchas alkyl lithium compounds, are typically employed to initiate thepolymerization. An advantage of free radical polymerization is thatreactions can typically be carried out under less rigorous conditionsthan ionic polymerizations. Free radical initiation systems also exhibita greater tolerance of trace impurities.

Examples of free radical initiators that are useful in the practice ofthe present invention are those known as “redox” initiators, such ascombinations of chelated iron salts, sodium formaldehyde sulfoxylate,and organic hydroperoxides. Representative of organic hydroperoxides arecumene hydroperoxide, paramenthane hydroperoxide, and tertiary butylhydroperoxide. Tertiary butyl hydroperoxide (t-BHP), tertiary butylperacetate (t-BPA) and “azo” initiators, such as azobisiobutyronitrile(AIBN), are preferred.

The reaction temperature is typically maintained in the range of 0° C.to 150° C. Temperatures between about 20° C. and 120° C. are generallypreferred and temperatures within the range of 60° C. to 100° C. arenormally most preferred. The reaction pressure is not critical. It istypically only sufficiently high to maintain liquid phase reactionconditions; it may be autogenic pressure, which will vary depending uponthe components of the reaction mixture and the temperature, or it may behigher, e.g., up to 1000 psi.

In batch operations, the polymerization time of functionalized dienemonomers can be varied as desired; it may vary, for example, from a fewminutes to several days. Polymerization in batch processes may beterminated when monomer is no longer absorbed, or earlier, if desired,e.g., if the reaction mixture becomes too viscous. In continuousoperations, the polymerization mixture may be passed through a reactorof any suitable design. The polymerization reactions in such cases aresuitably adjusted by varying the residence time. Residence times varywith the type of reactor system and range, for example, from 10 to 15minutes to 24 or more hours.

The concentration of monomer in the reaction mixture may vary upwardfrom 5 percent by weight of the reaction mixture, depending on theconditions employed; the range from 20 to 80 percent by weight ispreferred.

The polymerization reactions according to this invention may be carriedout in a suitable solvent that is liquid under the conditions ofreaction and relatively inert. The solvent may have the same number ofcarbon atoms per molecule as the diene reactant or it may be in adifferent boiling range. Preferred as solvents are alkane andcycloalkane hydrocarbons. Suitable solvents are, for example, hexane,cyclohexane, methylcyclohexane, or various saturated hydrocarbonmixtures. Aromatic hydrocarbons such as benzene, toluene,isopropylbenzene, xylene, or halogenated aromatic compounds such aschlorobenzene, bromobenzene, or orthodichlorobenzene may also beemployed. Other useful solvents include tetrahydrofuran and dioxane.

Conventional emulsion recipes may also be employed with the presentinvention; however, some restrictions and modifications may arise eitherfrom the polymerizable monomer itself, or the polymerization parameters.Ionic surfactants, known in the art, including sulfonate detergents andcarboxylate, sulfate, and phosphate soaps are useful in this invention.The level of ionic surfactant is computed based upon the total weight ofthe organic components and may range from about 2 to 30 parts by weightof ionic surfactant per 100 parts by weight of organic components.

Preferably the polymerization is carried out to complete functionalizeddiene monomer conversion in order to incorporate essentially all of thepolymerizable functional group-bearing monomer. Incremental addition, ora chain transfer agent, may be used in order to avoid excessive gelformation. Such minor modifications are within the skill of the artisan.After the polymerization is complete, the polymer is recovered from aslurry or solution of the polymer. A simple filtration may be adequateto separate polymer from diluent. Other means for separating polymerfrom diluent may be employed. The polymer may be treated, separately orwhile slurried in the reaction mixture, in order to separate residues.Such treatment may be with alcohols such as methanol, ethanol, orisopropanol, with acidified alcohols, or with other similar polarliquids. In many cases the polymers are obtained in hydrocarbonsolutions and the polymer can be recovered by coagulation with acidifiedalcohol, e.g., rapidly stirred methanol or isopropanol containing 2%hydrochloric acid. Following this initial coagulation,the polymers maybe washed several more times in methanol.

The functionalized diene monomers according to the present invention mayalso be polymerized with one or more comonomers. Some adjustments in thepolymerization recipe or reaction conditions may be necessary to obtaina satisfactory rate of polymer formation, depending on the amount offunctionalized monomer included and the other monomers involved.Examples of comonomers that are useful in the practice of this inventionare diene monomers such as butadiene, isoprene, and hexadienes. One may,in addition to the diene monomers, use a vinyl monomer such as styrene,α-methylstyrene, divinyl benzene, vinyl chloride, vinyl acetate,vinylidene chloride, methyl methacrylate, ethyl acrylate, vinylpyridine,acrylonitrile, methacrylonitrile, methacrylic acid, itaconic acid andacrylic acid. Mixtures of different functionalized monomers and mixturesof different comonomers may be used. The monomer charge ratio by weightis normally from about 0.10/99.9 to 99.9/0.10 functionalized monomer tocomonomer (including any additional vinyl monomer). A charge ratio byweight of about 5/95 to about 80/20 is preferred with 10/90 to 40/60 themost preferred. According to one embodiment, the weight ratio offunctionalized diene monomer to diene monomer to vinyl monomer may rangefrom 5:75:20 to 95:5:0. Ratios will vary depending on the amount ofchemical functionality desired to be incorporated and on the reactivityratios of the monomers in the particular polymerization system used.

The functionalized monomers of this invention offer a unique ability torandomly copolymerize with conjugated diolefin monomers in solutionpolymerizations that are conducted at temperatures of 20° C. or higher.The functionalized monomers of this invention can be incorporated intovirtually any type of rubbery polymer that is capable of being made bysolution polymerization with an anionic initiator or. The polymerizationemployed in synthesizing the rubbery polymers will normally be carriedout in a hydrocarbon solvent. Such hydrocarbon solvents are comprised ofone or more aromatic, paraffinic or cycloparaffinic compounds. Thesesolvents will normally contain from about 4 to about 10 carbon atoms permolecule and will be liquid under the conditions of the polymerization.Some representative examples of suitable organic solvents includepentane, isooctane, cyclohexane, methylcyclohexane, isohexane,n-heptane, n-octane, n-hexane, benzene, toluene, xylene, ethylbenzene,diethylbenzene, isobutylbenzene, petroleum ether, kerosene, petroleumspirits, petroleum naphtha, and the like, alone or in admixture.

In the solution polymerization, there will normally be from 5 to 30weight percent monomers in the polymerization medium. Suchpolymerization media are, of course, comprised of the organic solventand monomers. In most cases, it will be preferred for the polymerizationmedium to contain from 10 to 25 weight percent monomers. It is generallymore preferred for the polymerization medium to contain 15 to 20 weightpercent monomers.

The synthetic rubbers made by the process of this invention can be madeby random copolymerization of the functionalized monomer with aconjugated diolefin monomer or by the random terpolymerization of thefunctionalized monomer with a conjugated diolefin monomer and a vinylaromatic monomer. It is, of course, also possible to make such rubberypolymers by polymerizing a mixture of conjugated diolefin monomers withone or more ethylenically unsaturated monomers, such as vinyl aromaticmonomers. The conjugated diolefin monomers which can be utilized in thesynthesis of rubbery polymers which can be coupled in accordance withthis invention generally contain from 4 to 12 carbon atoms. Thosecontaining from 4 to 8 carbon atoms are generally preferred forcommercial purposes. For similar reasons, 1,3-butadiene and isoprene arethe most commonly utilized conjugated diolefin monomers. Some additionalconjugated diolefin monomers that can be utilized include2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene,2-phenyl-1,3-butadiene, and the like, alone or in admixture.

Some representative examples of ethylenically unsaturated monomers thatcan potentially be polymerized into rubbery polymers that contain thefunctionalized monomers of this invention include alkyl acrylates, suchas methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylateand the like; vinylidene monomers having one or more terminal CH₂═CH—groups; vinyl aromatics such as styrene, α-methylstyrene, bromostyrene,chlorostyrene, fluorostyrene and the like; α-olefins such as ethylene,propylene, 1-butene and the like; vinyl halides, such as vinylbromide,chloroethene (vinylchloride), vinylfluoride, vinyliodide,1,2-dibromoethene, 1,1-dichloroethene (vinylidene chloride),1,2-dichloroethene and the like; vinyl esters, such as vinyl acetate;α,β-olefinically unsaturated nitriles, such as acrylonitrile andmethacrylonitrile; α,β-olefinically unsaturated amides, such asacrylamide, N-methyl acrylamide, N,N-dimethylacrylamide, methacrylamideand the like.

Rubbery polymers which are copolymers of one or more diene monomers withone or more other ethylenically unsaturated monomers will normallycontain from about 50 weight percent to about 99 weight percentconjugated diolefin monomers and from about 1 weight percent to about 50weight percent of the other ethylenically unsaturated monomers inaddition to the conjugated diolefin monomers. For example, copolymers ofconjugated diolefin monomers with vinylaromatic monomers, such asstyrene-butadiene rubbers which contain from 50 to 95 weight percentconjugated diolefin monomers and from 5 to 50 weight percentvinylaromatic monomers, are useful in many applications.

Vinyl aromatic monomers are probably the most important group ofethylenically unsaturated monomers which are commonly incorporated intopolydiene rubbers. Such vinyl aromatic monomers are, of course, selectedso as to be copolymerizable with the conjugated diolefin monomers beingutilized. Generally, any vinyl aromatic monomer which is known topolymerize with organolithium initiators can be used. Such vinylaromatic monomers typically contain from 8 to 20 carbon atoms. Usually,the vinyl aromatic monomer will contain from 8 to 14 carbon atoms. Themost widely used vinyl aromatic monomer is styrene. Some examples ofvinyl aromatic monomers that can be utilized include styrene,1-vinylnaphthalene, 2-vinylnaphthalene, α-methylstyrene,4-phenylstyrene, 3-methylstyrene and the like.

Some representative examples of rubbery polymers that can befunctionalized with the functionalized monomers of this inventioninclude polybutadiene, polyisoprene, styrene-butadiene rubber (SBR),α-methylstyrene-butadiene rubber, α-methylstyrene-isoprene rubber,styrene-isoprene-butadiene rubber (SIBR), styrene-isoprene rubber (SIR),isoprene-butadiene rubber (IBR), α-methylstyrene-isoprene-butadienerubber and α-methylstyrene-styrene-isoprene-butadiene rubber. In caseswhere the rubbery polymer is comprised of repeat units that are derivedfrom two or more monomers, the repeat units which are derived from thedifferent monomers, including the functionalized monomers, will normallybe distributed in an essentially random manner. The repeat units thatare derived from the monomers differ from the monomer in that a doublebond is normally consumed in by the polymerization reaction.

The rubbery polymer can be made by solution polymerization in a batchprocess by in a continuous process by continuously charging at least oneconjugated diolefin monomer, the functionalized monomer, and anyadditional monomers into a polymerization zone. The polymerization zonewill typically be a polymerization reactor or a series of polymerizationreactors. The polymerization zone will normally provide agitation tokeep the monomers, polymer, initiator, and modifier well dispersedthroughout the organic solvent the polymerization zone. Such continuouspolymerizations are typically conducted in a multiple reactor system.The rubbery polymer synthesized is continuously withdrawn from thepolymerization zone. The monomer conversion attained in thepolymerization zone will normally be at least about 85 percent. It ispreferred for the monomer conversion to be at least about 90 percent.

The polymerization will be initiated with an anionic initiator, such asan alkyl lithium compound. The alkyl lithium compounds that can be usedwill typically contain from 1 to about 8 carbon atoms, such as n-butyllithium,

The amount of the lithium initiator utilized will vary with the monomersbeing polymerized and with the molecular weight that is desired for thepolymer being synthesized. However, as a general rule, from 0.01 to 1phm (parts per 100 parts by weight of monomer) of the lithium initiatorwill be utilized. In most cases, from 0.01 to 0.1 phm of the lithiuminitiator will be utilized with it being preferred to utilize 0.025 to0.07 phm of the lithium initiator.

The polymerization process of this invention is normally conducted inthe presence of polar modifiers, such as alkyltetrahydrofurfuryl ethers.Some representative examples of specific polar modifiers that can beused include methyltetrahydrofurfuryl ether, ethyltetrahydrofurfurylether, propyltetrahydrofurfuryl ether, butyltetrahydrofurfuryl ether,hexyltetrahydrofurfuryl ether, octyltetrahydrofurfuryl ether,dodecyltetrahydrofurfuryl ether, diethyl ether, di-n-propyl ether,diisopropyl ether, di-n-butyl ether, tetrahydrofuran, dioxane, ethyleneglycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycoldimethyl ether, diethylene glycol diethyl ether, triethylene glycoldimethyl ether, trimethylamine, triethylamine,N,N,N′,N′-tetramethylethylenediamine, N-methyl morpholine, N-ethylmorpholine, or N-phenyl morpholine.

The polar modifier will typically be employed at a level wherein themolar ratio of the polar modifier to the lithium initiator is within therange of about 0.01:1 to about 5:1. The molar ratio of the polarmodifier to the lithium initiator will more typically be within therange of about 0.1:1 to about 4:1. It is generally preferred for themolar ratio of polar modifier to the lithium initiator to be within therange of about 0.25:1 to about 3:1. It is generally most preferred forthe molar ratio of polar modifier to the lithium initiator to be withinthe range of about 0.5:1 to about 3:2.

The polymerization can optionally be conducted utilizing an oligomericoxolanyl alkane as the modifier. Such oligomeric oxolanyl alkanes willtypically be of a structural formula selected from the group consistingof:

wherein n represents an integer from 1 to 5, wherein m represents aninteger from 3 to 5, wherein R₁, R₂, R₃, R₄, R₅, and R₆ can be the sameor different, and wherein R₁, R₂, R₃, R₄, R₅, and R₆ represent a memberselected from the group consisting of hydrogen atoms and alkyl groupscontaining from 1 to about 8 carbon atoms. It is typically preferred forR₁, R₂, R₃, R₄, R₅, and R₆ represent a member selected from the groupconsisting of hydrogen atoms and alkyl groups containing from 1 to 4carbon atoms.

The polymerization temperature utilized can vary over a broad range offrom about −20° C. to about 180° C. In most cases, a polymerizationtemperature within the range of about 30° C. to about 125° C. will beutilized. It is typically preferred for the polymerization temperatureto be within the range of about 45° C. to about 100° C. It is typicallymost preferred for the polymerization temperature to be within the rangeof about 60° C. to about 90° C. The pressure used will normally besufficient to maintain a substantially liquid phase under the conditionsof the polymerization reaction.

The polymerization is conducted for a length of time sufficient topermit substantially complete polymerization of monomers. In otherwords, the polymerization is normally carried out until high conversionsof at least about 85 percent are attained. The polymerization is thenterminated by the addition of an agent, such as an alcohol, aterminating agent, or a coupling agent. For example, a tin halide and/orsilicon halide can be used as a coupling agent. The tin halide and/orthe silicon halide are continuously added in cases where asymmetricalcoupling is desired. This continuous addition of tin coupling agentand/or the silicon coupling agent is normally done in a reaction zoneseparate from the zone where the bulk of the polymerization isoccurring. The coupling agents will normally be added in a separatereaction vessel after the desired degree of conversion has beenattained. The coupling agents can be added in a hydrocarbon solution,e.g., in cyclohexane, to the polymerization admixture with suitablemixing for distribution and reaction. In other words, the coupling willtypically be added only after a high degree of conversion has alreadybeen attained. For instance, the coupling agent will normally be addedonly after a monomer conversion of greater than about 85 percent hasbeen realized. It will typically be preferred for the monomer conversionto reach at least about 90 percent before the coupling agent is added.

The tin halides used as coupling agents will normally be tintetrahalides, such as tin tetrachloride, tin tetrabromide, tintetrafluoride or tin tetraiodide. However, tin trihalides can alsooptionally be used. Polymers coupled with tin trihalides having amaximum of three arms. This is, of course, in contrast to polymerscoupled with tin tetrahalides which have a maximum of four arms. Toinduce a higher level of branching, tin tetrahalides are normallypreferred. As a general rule, tin tetrachloride is most preferred.

The silicon coupling agents that can be used will normally be silicontetrahalides, such as silicon tetrachloride, silicon tetrabromide,silicon tetrafluoride or silicon tetraiodide. However, silicontrihalides can also optionally be used. Polymers coupled with silicontrihalides having a maximum of three arms. This is, of course, incontrast to polymers coupled with silicon tetrahalides which have amaximum of four arms. To induce a higher level of branching, silicontetrahalides are normally preferred. As a general rule, silicontetrachloride is most preferred of the silicon coupling agents.

A combination of a tin halide and a silicon halide can optionally beused to couple the rubbery polymer. By using such a combination of tinand silicon coupling agents improved properties for tire rubbers, suchas lower hysteresis, can be attained. It is particularly desirable toutilize a combination of tin and silicon coupling agents in tire treadcompounds that contain both silica and carbon black. In such cases, themolar ratio of the tin halide to the silicon halide employed in couplingthe rubbery polymer will normally be within the range, of 20:80 to 95:5.The molar ratio of the tin halide to the silicon halide employed incoupling the rubbery polymer will more typically be within the range of40:60 to 90:10. The molar ratio of the tin halide to the silicon halideemployed in coupling the rubbery polymer will preferably be within therange of 60:40 to 85:15. The molar ratio of the tin halide to thesilicon halide employed in coupling the rubbery polymer will mostpreferably be within the range of 65:35 to 80:20.

Broadly, and exemplary, a range of about 0.01 to 4.5 milliequivalents oftin coupling agent (tin halide and silicon halide) is employed per 100grams of the rubbery polymer. It is normally preferred to utilize about0.01 to about 1.5 milliequivalents of the coupling agent per 100 gramsof polymer to obtain the desired Mooney viscosity. The larger quantitiestend to result in production of polymers containing terminally reactivegroups or insufficient coupling. One equivalent of tin coupling agentper equivalent of lithium is considered an optimum amount for maximumbranching. For instance, if a mixture tin tetrahalide and silicontetrahalide is used as the coupling agent, one mole of the couplingagent would be utilized per four moles of live lithium ends. In caseswhere a mixture of tin trihalide and silicon trihalide is used as thecoupling agent, one mole of the coupling agent will optimally beutilized for every three moles of live lithium ends. The coupling agentcan be added in a hydrocarbon solution, e.g., in cyclohexane, to thepolymerization admixture in the reactor with suitable mixing fordistribution and reaction.

After the coupling has been completed, a tertiary chelating alkyl1,2-ethylene diamine or a metal salt of a cyclic alcohol can optionallybe added to the polymer cement to stabilize the coupled rubbery polymer.The tertiary chelating amines that can be used are normally chelatingalkyl diamines of the structural formula:

wherein n represents an integer from 1 to about 6, wherein A representsan alkylene group containing from 1 to about 6 carbon atoms and whereinR′, R″, R′″ and R″″ can be the same or different and represent alkylgroups containing from 1 to about 6 carbon atoms. The alkylene group Ais of the formula —(—CH₂—)_(m) wherein m is an integer from 1 to about6. The alkylene group will typically contain from 1 to 4 carbon atoms (mwill be 1 to 4) and will preferably contain 2 carbon atoms. In mostcases, n will be an integer from 1 to about 3 with it being preferredfor n to be 1. It is preferred for R′, R″, R′″ and R″″ to representalkyl groups which contain from 1 to 3 carbon atoms. In most cases, R′,R″, R′″ and R″″ will represent methyl groups.

In most cases, from about 0.01 phr (parts by weight per 100 parts byweight of dry rubber) to about 2 phr of the chelating alkyl 1,2-ethylenediamine or metal salt of the cyclic alcohol will be added to the polymercement to stabilize the rubbery polymer. Typically, from about.0.05 phrto about 1 phr of the chelating alkyl 1,2-ethylene diamine or metal saltof the cyclic alcohol will be added. More typically, from about 0.1 phrto about 0.6 phr of the chelating alkyl 1,2-ethylene diamine or themetal salt of the cyclic alcohol will be added to the polymer cement tostabilize the rubbery polymer.

The terminating agents that can be used to stop the polymerization andto “terminate” the living rubbery polymer include tin monohalides,silicon monohalides, N,N,N′,N′-tetradialkyldiamino-benzophenones (suchas tetramethyldiaminobenzophenone and the like),N,N-dialkylamino-benzaldehydes (such as dimethylaminobenzaldehyde andthe like), 1,3-dialkyl-2-imidazolidinones (such as1,3-dimethyl-2-imidazolidinone and the like), 1-alkyl substitutedpyrrolidinones; 1-aryl substituted pyrrolidinones,dialkyl-dicycloalkyl-carbodiimides containing from about 5 to about 20carbon atoms, and dicycloalkyl-carbodiimides containing from about 5 toabout 20 carbon atoms.

After the termination step, and optionally the stabilization step, hasbeen completed, the rubbery polymer can be recovered from the organicsolvent. The coupled rubbery polymer can be recovered from the organicsolvent and residue by means such as chemical (alcohol) coagulation,thermal desolventization, or other suitable method. For instance, it isoften desirable to precipitate the rubbery polymer from the organicsolvent by the addition of lower alcohols containing from about 1 toabout 4 carbon atoms to the polymer solution. Suitable lower alcoholsfor precipitation of the rubber from the polymer cement includemethanol, ethanol, isopropyl alcohol, normal-propyl alcohol and t-butylalcohol. The utilization of lower alcohols to precipitate the rubberypolymer from the polymer cement also “terminates” any remaining livingpolymer by inactivating lithium end groups. After the coupled rubberypolymer is recovered from the solution, steam-stripping can be employedto reduce the level of volatile organic compounds in the coupled rubberypolymer. Additionally, the organic solvent can be removed from therubbery polymer by drum drying, extruder drying, vacuum drying, and thelike.

The polymers of the present invention can be used alone or incombination with other elastomers to prepare an rubber compounds, suchas a tire treadstock, sidewall stock or other tire component stockcompounds. In a tire of the invention, at least one such component isproduced from a vulcanizable elastomeric or rubber composition. Forexample, the rubbery polymer made by the process of this invention canbe blended with any conventionally employed treadstock rubber whichincludes natural rubber, synthetic rubber and blends thereof. Suchrubbers are well known to those skilled in the art and include syntheticpolyisoprene rubber, styrene/butadiene rubber (SBR), polybutadiene,butyl rubber, Neoprene, ethylene/propylene rubber,ethylene/propylene/diene rubber (EPDM), acrylonitrile/butadiene rubber(NBR), silicone rubber, the fluoroelastomers, ethylene acrylic rubber,ethylene vinyl acetate copolymer (EVA), epichlorohydrin rubbers,chlorinated polyethylene rubbers, chlorosulfonated polyethylene rubbers,hydrogenated nitrile rubber, tetrafluoroethylene/propylene rubber andthe like.

When the rubbery polymers made by the process of the present inventionare blended with conventional rubbers, the amounts can vary widely suchas between 10 and 99 percent by weight. In any case, tires made withsynthetic rubbers that are synthesized utilizing the technique of thisinvention exhibit decreased rolling resistance. The greatest benefitsare realized in cases where the tire tread compound is made with therubbery polymer synthesized utilizing the technique of this invention.However, benefits can also by attained in cases where at least onestructural element of the tire, such as subtread, sidewalls, body plyskim, or bead filler, is comprised of the rubbery.

The synthetic rubbers made in accordance with this invention can becompounded with carbon black in amounts ranging from about 5 to about100 phr (parts by weight per 100 parts by weight of rubber), with about5 to about 80 phr being preferred ,and with about 40 to about 70 phrbeing more preferred. The carbon blacks may include any of the commonlyavailable, commercially-produced carbon blacks but those having asurface area (EMSA) of at least 20 m²/g and more preferably at least 35m²/g up to 200 m²/g or higher are preferred. Surface area values used inthis application are those determined by ASTM test D-1765 using thecetyltrimethyl-ammonium bromide (CTAB) technique.

Among the useful carbon blacks are furnace black, channel blacks andlamp blacks. More specifically, examples of the carbon blacks includesuper abrasion furnace (SAF) blacks, high abrasion furnace (HAF) blacks,fast extrusion furnace (FEF) blacks, fine furnace (FF) blacks,intermediate super abrasion furnace (ISAF) blacks, semi-reinforcingfurnace (SRF) blacks, medium processing channel blacks, hard processingchannel blacks and conducting channel blacks. Other carbon blacks whichmay be utilized include acetylene blacks. Mixtures of two or more of theabove blacks can be used in preparing the carbon black products of theinvention. Typical values for surface areas of usable carbon blacks aresummarized in the following table.

Carbon Black ASTM Designation (D-1765-82a) Surface Area (D-3765) N-110126 m²/g  N-220 111 m²/g  N-330 83 m²/g N-339 95 m²/g N-550 42 m²/gN-660 35 m²/g

The carbon blacks utilized in the preparation of rubber compounds may bein pelletized form or an unpelletized flocculent mass. Preferably, formore uniform mixing, unpelletized carbon black is preferred. Thereinforced rubber compounds can be cured in a conventional manner withabout 0.5 to about 4 phr of known vulcanizing agents. For example,sulfur or peroxide-based curing systems may be employed. For a generaldisclosure of suitable vulcanizing agents one can refer to Kirk-Othmer,Encyclopedia of Chemical Technology, 3rd ed., Wiley Interscience, N.Y.1982, Vol. 20, pp. 365-468, particularly “Vulcanization Agents andAuxiliary Materials” pp. 390-402. Vulcanizing agents can, of curse, beused alone or in combination. Vulcanizable elastomeric or rubbercompositions can be prepared by compounding or mixing the polymersthereof with carbon black and other conventional rubber additives suchas fillers, plasticizers, antioxidants, curing agents and the like,using standard rubber mixing equipment and procedures and conventionalamounts of such additives.

The functionalized styrene monomer can be synthesized by reacting asecondary amine with vinyl benzyl halide, such as vinyl benzyl chloride,in the presence of a strong base to produce the functionalized styrenemonomer. This procedure can be depicted as follows:

This reaction is typically conducted at a temperature which is withinthe range of about −20° C. to about 40° C., and is preferably conductedat a temperature which is within the range of about −10° C. to about 30°C. This reaction will most preferable be conducted at a temperaturewhich is within the range of about 0° C. to about 25° C. The strong basecan be selected from a large variety of organic or inorganic compounds.Examples of organic bases are aromatic and aliphatic amines, pyridines,such as triethylamine, aniline, and pyridine. Examples of suitableinorganic bases are the salts of weak mineral acids such has sodiumcarbonate, calcium carbonate, sodium hyrdroxide, calcium hydroxide, andaluminum hyrdoxide. After the reaction has been completed volatilecompounds are removed under reduced pressure yielding the product as aviscous residue.

Functionalized monomers that contain cyclic amines can also be made bythe same reaction scheme wherein a cyclic secondary amine is employed inthe first step of the reaction. This reaction scheme can be depicted asfollows:

The functionalized styrene monomers that can be used in the practice ofthis invention are typically of the structural formula:

wherein R represents an alkyl group containing from 1 to about 10 carbonatoms or a hydrogen atom, and wherein R¹ and R² can be the same ordifferent and represent hydrogen atoms or a moiety selected from thegroup consisting of

wherein R³ groups can be the same or different and represent a memberselected from the group consisting of alkyl groups containing from 1 toabout 10 carbon atoms, aryl groups, allyl groups, and alklyoxy groupshaving the structural formula —(CH₂)_(y)—O—(CH₂)_(z)—CH₃, wherein yrepresents an integer from 1 to 10, wherein z represents an integer from1 to 10, wherein Z represents a nitrogen containing heterocycliccompound, wherein R⁴ represents a member selected from the groupconsisting of alkyl groups containing from 1 to about 10 carbon atoms,aryl groups, and allyl groups, and wherein x and represents an integerfrom 1 to about 10, and wherein n represents an integer from about 1 toabout 10, with the proviso that R¹ and R² can not both be hydrogenatoms. In these monomers R will typically represent a hydrogen atomtypically represent a hydrogen atom or a methyl group, and x willtypically represent an integer from 1 to 4. In most cases x will be 1.In one embodiment of this invention, R3 and R4 can represent alkylgroups that contain from 1 to about 4 carbon atoms, aryl groups thatcontain from about 6 to about 18 carbon atoms, or allyl groups thatcontain from about 3 to about 18 carbon atoms.

Functionalized styrene monomers of the following structural formulas:

wherein n represents an integer from 4 to about 10 are highly useful inthe practice of this invention. In these functionalized styrene monomersn will normally represents 4 or 6.

The nitrogen containing heterocyclic group (Z group) will normally beone of the following moieties:

wherein R⁵ groups can be the same or different and represent a memberselected from the group consisting of alkyl groups containing from 1 toabout 10 carbon atoms, aryl groups, allyl groups, and alkoxy groups, andwherein Y represents oxygen, sulfur, or a methylene group.

This invention is illustrated by the following examples that are merelyfor the purpose of illustration and are not to be regarded as limitingthe scope of the invention or the manner in which it can be practiced.Unless specifically indicated otherwise, parts and percentages are givenby weight.

EXAMPLES Synthesis of 1-[(4-Ethenylphenyl)methyl]-pyrrolidine

A 1 L (liter) round bottom flask was charged with hexane (400 mL) and4-vinylbenzyl chloride (104.4 g, 0.68 moles). The reaction flask wasplaced into an ice/water bath and stirred with a magnetic stir bar. Twoequivalents of pyrrolidine (130 g, 1.37 moles) were added over thecourse of 1 hour. After completed addition the ice/water bath wasremoved and the reaction was stirred at room temperature overnight.Solids were removed via vacuum filtration and volatiles were removedunder vacuum to render the product in quantitative yield.

Materials

Butadiene premixes were made using distilled 1,3-butadiene supplied byExxon and hexanes (a mixture of hexane isomers) supplied by AshlandChemicals, and subsequently passed over an activated silica gel/3Amolecular sieve column under dry nitrogen prior to use. Styrene premixeswere made using styrene and hexanes, both supplied by Ashland Chemicals,and subsequently passed over an activated silica gel/3A molecularsieve/sodium hydroxide column under dry nitrogen prior to use.N′,N′,N,N-tetramethylethylenediamine (TMEDA) was purchased from AldrichChemical, diluted to 1.60M using anhydrous hexane, and held under drynitrogen and over 3A molecular sieves. A solution of n-butyllithium(n-BuLi) in hexanes (1.60M) was obtained from Chemetall Foote and usedwithout further treatment. A solution of pyrrolidinopropyl lithium(PP-Li, chain extended with isoprene) in cyclohexane (0.93M) wasobtained from Chemetall Foote and used without further treatment.N-methylpyrrolidino-substituted styrene was diluted to 1.87M usinganhydrous hexane.

POLYMERIZATION Sample A

To a one-gallon (3.785 liter) glass bowl reactor was added 1,428 gramsbutadiene premix at 18.2 weight.percent butadiene and 572 grams styrenepremix at 15.2 weight percent styrene. Following the monomer premixaddition, 1.87 mmoles of TMEDA (1:1 molar ratio to lithium) was injectedinto the reactor. Finally, 2.35 mmoles of n-BuLi (including 0.48 mmolesas scavenger) was injected into the reactor, followed by approximately 4mL of dried hexanes to flush the injection port. The reactiontemperature was maintained at 65° C. The polymerization was terminatedafter two hours and full conversion using a slight molar excess ofethanol to n-BuLi. The terminated cement was stabilized using2,6-di-t-butyl-4-methylphenol (BHT) at 1.0 phr polymer and subsequentlydried using a lab-scale steam-heated drum dryer.

Sample B

To a one-gallon (3.785 liter) glass bowl reactor was added 1,428 gramsbutadiene premix at 18.2 weight percent butadiene and 572 grams styrenepremix at 15.2 weight percent styrene. Following the monomer premixaddition, 3.46 mmoles (2:1 molar ratio to lithium, ˜0.2 weight percenttotal monomer) of N-methylpyrrolidino-substituted styrene monomer wasinjected into the reactor, followed by approximately 4 mL of driedhexanes to flush the injector port. Next, 1.73 mmoles of TMEDA (1:1molar ratio to lithium) was injected into the reactor. Finally, 2.19mmoles of n-BuLi (including 0.46 mmoles as scavenger) was injected intothe reactor, followed by approximately 4 mL of dried hexanes to flushthe injection port. The reaction temperature was maintained at 65° C.The polymerization was terminated after two hours and full conversionusing a slight molar excess of ethanol to n-BuLi. The terminated cementwas stabilized using BHT at 1.0 phr polymer and subsequently dried usinga lab-scale steam-heated drum dryer.

Sample C

To a one-gallon (3.785 liter) glass bowl reactor was added 1,451 gramsbutadiene premix at 17.2 weight percent butadiene and 549 grams styrenepremix at 15.2 weight percent styrene. Following the monomer premixaddition, 17.95 mmoles (˜1.0 weight percent total monomer) ofN-methylpyrrolidino-substituted styrene monomer was injected into thereactor, followed by approximately 4 mL of dried hexanes to flush theinjector port. Next, 1.66 mmoles of TMEDA (1:1 molar ratio to lithium)was injected into the reactor. Finally, 3.36 mmoles of n-BuLi (including1.70 mmoles as scavenger) was injected into the reactor, followed byapproximately 4 mL of dried hexanes to flush the injection port. Thereaction temperature was maintained at 65° C. The polymerization wasterminated after two hours and full conversion using a slight molarexcess of ethanol to n-BuLi. The terminated cement was stabilized usingBHT at 1.0 phr polymer and subsequently dried using a lab-scalesteam-heated drum dryer.

Sample D

To a one-gallon (3.785 liter) glass bowl reactor was added 1,451 gramsbutadiene premix at 17.2 weight percent butadiene and 549 grams styrenepremix at 15.2 weight percent styrene. Following the monomer premixaddition, 1.90 mmoles of TMEDA (1:1 molar ratio to lithium) was injectedinto the reactor. Finally, 2.20 mmoles of n-BuLi (including 0.30 mmolesas scavenger) was injected into the reactor, followed by approximately 4mL of dried hexanes to flush the injection port. The reactiontemperature was maintained at 65° C. After two hours, 3.80 mmoles ofN-methylpyrrolidino-substituted styrene monomer (2:1 molar ratio tolithium, ˜0.2 weight percent total monomer) was injected into thereactor, followed by approximately 4 mL of dried hexanes to flush theinjection port. After 15 minutes, the polymerization was terminatedusing a slight molar excess of ethanol to n-BuLi. The terminated cementwas stabilized using BHT at 1.0 phr polymer and subsequently dried usinga lab-scale steam-heated drum dryer.

Sample E

To a one-gallon (3.785 liter) glass bowl reactor was added 1,439 gramsbutadiene premix at 17.7 weight percent butadiene and 561 grams styrenepremix at 15.2 weight percent styrene. Following the monomer premixaddition, 1.74 mmoles of TMEDA (1:1 molar ratio to lithium) was injectedinto the reactor. Finally, 2.13 mmoles of PP-Li (including 0.39 mmolesas scavenger) was injected into the reactor, followed by approximately 4mL of dried hexanes to flush the injection port. The reactiontemperature was maintained at 65° C. The polymerization was terminatedafter two hours and full conversion using a slight molar excess ofethanol to lithium. The terminated cement was stabilized using BHT at1.0 phr polymer and subsequently dried using a lab-scale steam-heateddrum dryer.

Characterization

Several standard techniques were utilized to characterize both thecement solutions and the dried polymer products. During polymerization,essentially complete monomer conversion after two hours reaction timewas confirmed by gas chromatography on a Hewlett Packard 5890 Series IIGas Chromatogram with a 60 m×0.250 mm DB-5 column at 0.25 micron. Sizeexclusion chromatography SEC was performed via Polymer Labs multiple Cmicrogel columns (with guard column) using THF as the carrier solventand for sample preparation. Multi-angle laser light scatteringmeasurements were carried out using a Wyatt Technologies miniDawn lightscattering detector and a Hewlett Packard 1047A refractive indexdetector. Glass transition temperature analyses were performed on a TAInstruments 2910 DSC using a 10° C./min linear heat rate. Mooney Large ¼viscosity measurements were acquired using a Monsanto Mooney Viscometer.Table 1 shows the characterization results for the five samplessynthesized for this study.

TABLE 1 Characterization results for Samples A-E. Sample ID CommentMooney Mn (g/mole) Mw (g/mole) PDI Onset Tg (C.) Sample A n-BuLi control60 212,800 224,300 1.05 −33 Sample B ˜0.2 wt % functional monomer,random 66 214,100 227,700 1.06 −37 Sample C ˜1.0 wt % functionalmonomer, random 62 252,300 306,900 1.22 −40 Sample D ˜0.2 wt %functional monomer, capped 65 240,600 276,800 1.15 −36 Sample E PP-Li 70227,100 245,100 1.08 −36

Compounding

Samples A-E were mixed in a standard carbon black formulation using a 75cc Haake mixer. The formulation, included 100 parts polymer, 55 partscarbon black, 10 parts process oil, 3 parts zinc oxide, 2 parts stearicacid and 1.5 parts antioxidant in the nonproductive stage, and aftercooling, an additional 1.2 parts sulfenamide accelerator and 1.4 partssulfur in the productive stage. The nonproductive stage was mixed forfive minutes at 120° C. and 100 rpm, and the productive stage was mixedfor three minutes at 100° C. and 60 rpm.

Compound Analysis

A Monsanto Rubber Process Analyzer 2000 was used to measure theviscoelastic properties of the five compounded samples. Of particularinterest was the relationship between tan delta at 5% strain, 1.0 Hz and100° C. versus uncured storage modulus G′ at 15% strain, 8.33 Hz and100° C. This relationship gives an indication of the hysteresis of thecompound (lower tan delta is better) versus its processability (lower G′is better). Table 2 shows the results of the analysis for the fivecompounded samples. One important result is that at equal modulus, the1.0 wt. % functional monomer sample is approximately 23% less hystereticthan the PP-Li sample.

TABLE 2 Viscoelastic data for five compounded samples. G′ at tan deltaat tan delta % Sample ID Comment 8.33 Hz 5% strain improvement Sample An-BuLi control 562 0.173 — Sample B ˜0.2 wt % functional 606 0.135 22.3%monomer, random Sample C ˜1.0 wt % functional 645 0.106 38.7% monomer,random Sample D ˜0.2 wt % functional 584 0.149 13.9% monomer, cappedSample E PP-Li 644 0.137 21.1%

While certain representative embodiments and details have been shown forthe purpose of illustrating the subject invention, it will be apparentto those skilled in this art that various changes and modifications canbe made therein without departing from the scope of the subjectinvention.

What is claimed is:
 1. A rubbery polymer which is comprised of repeatunits that are derived from (1) at least one conjugated diolefinmonomer, and (2) at least one functionalized monomer having a structuralformula selected from the group consisting of

wherein R represents an alkyl group containing from 1 to about 10 carbonatoms or a hydrogen atom, and wherein R¹ and R² can be the same ordifferent and represent hydrogen atoms or a moiety selected from thegroup consisting of

wherein Z represents a nitrogen containing heterocyclic compound,wherein R⁴ represents a member selected from the group consisting ofalkyl groups containing from 1 to about 10 carbon atoms, aryl groups,and allyl groups, and wherein x represents an integer from 1 to about10, with the proviso that R¹ and R² can not both be hydrogen atoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 1 to about 10, with the proviso that the sumof n and m is at least 4;

wherein n represents an integer from 1 to about 10, and wherein R and R′can be the same or different and represent alkyl groups containing from1 to about 10 carbon atoms;

wherein n represents an integer from 1 to about 10 and wherein mrepresents an integer from 4 to about 10;

wherein x represents an integer from about 1 to about 10, wherein nrepresents an integer from 1 to about 10 and wherein m represents aninteger from 1 to about 10, with the proviso that the sum of n and m isat least 4;

wherein R represents a hydrogen atom or an alkyl group containing from 1to about 10 carbon atoms, wherein n represents an integer from 1 toabout 10, and wherein m represents an integer from 1 to about 10, withthe proviso that the sum of n and m is at least 4; and

wherein n represents an integer from 1 to about 10, wherein m representsan integer from 1 to about 10, wherein x represents an integer from 1 toabout 10, and wherein y represents an integer from 1 to about
 10. 2. Arubbery composition which is comprised of (1) a filler and (2) a rubberypolymer as specified in claim
 1. 3. A rubbery composition as specifiedin claim 2 wherein the filler is selected from the group consisting ofcarbon black, silica, starch, and clay.
 4. A rubbery composition asspecified in claim 2 wherein said rubbery composition is cured.
 5. Arubbery composition as specified in claim 4 wherein said rubberycomposition is cured with sulfur.
 6. A rubbery polymer as specified inclaim 1 wherein the functionalized monomer is of the structural formula:

wherein n represents the integer
 4. 7. A rubbery polymer as specified inclaim 1 wherein the functionalized monomer is of the structural formula:

wherein n represents the integer
 6. 8. A rubbery polymer as specified inclaim 1 wherein the repeat units in the rubbery polymer are derived fromat least one conjugated diolefin monomer and a functionalized monomerhaving the structural formula:

wherein n represents an integer from 4 to about
 10. 9. A rubbery polymeras specified in claim 8 wherein n represents 4 or
 6. 10. A rubberypolymer as specified in claim 1 wherein from about 0.2 weight percent toabout 50 weight percent of the repeat units in the rubbery polymer arederived from the functionalized monomer.
 11. A rubbery polymer asspecified in claim 1 wherein said rubbery polymer is coupled with a tinhalide and/or a silicon halide.
 12. A rubbery polymer as specified inclaim 1 wherein from about 0.2 weight percent to about 10 weight percentof the repeat units in the rubbery polymer are derived from thefunctionalized monomer.
 13. A rubbery polymer as specified in claim 1wherein the repeat units in the rubbery polymer are derived from afunctionalized monomer having the structural formula:

wherein x represents and integer from 4 to about 10, and wherein nrepresents an integer from 4 to about
 10. 14. A rubbery polymer asspecified in claim 13 wherein x represents an integer from 1 to
 4. 15. Arubbery polymer as specified in claim 14 wherein n represents an integerfrom 4 to about
 10. 16. A rubbery polymer as specified in claim 14wherein n represents
 4. 17. A rubbery polymer as specified in claim 14wherein n represents
 6. 18. A rubbery polymer as specified in claim 15wherein from about 0.2 weight percent to about 10 weight percent of therepeat units in the rubbery polymer are derived from the functionalizedmonomer.
 19. A rubbery polymer specified in claim 1 wherein R¹represents


20. A rubber polymer specified in claim 19 wherein R⁴ represents amember selected from the group consisting of